They said it could never happen in the US. At the foot of Wall Street, in the belly of the beast of aggressive market finance, 2,000 protesters demonstrating against corporate greed are attempting to push through a police barrier and occupy the iconic street.

They said it could never happen in the US. At the foot of Wall Street, in the belly of the beast of aggressive market finance, 2,000 protesters demonstrating against corporate greed are attempting to push through a police barrier and occupy the iconic street.

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The NYPD are beating them back with mace and batons, one white-shirted officer lashing into the crowd indiscriminately with his nightstick.

The air tastes of pepper spray and there are screams from the crowd. “Who the f*** are you protecting?” they chant. The Obama generation is beginning to receive an ugly answer to that most basic of political inquiries.

These protesters are part of a breakout march from the Occupy Wall Street demonstration in Manhattan's Liberty Plaza, which has now been in place for almost three weeks. Copycat demonstrations against economic injustice are springing up in cities across the US, and many thousands are involved.

Two hours earlier, a crowd of 20,000 students, labour members, activists and angry citizens are chanting over the sound of drums that “the people, united, will never be defeated!”

Labour unions have been swift to come out in support of the occupiers and rally in Foley Square, taking up their mantra: “We are the 99%” — the majority of the American people who have been cheated out of their share in the nation's wealth by the remaining “1%”.

“We are here to thank you!” a worker involved in the strike against Verizon tells the crowd. “We have to take back this city, take back our democracy.”

The process of taking back democracy, however, is rarely painless. As the cry goes up to “march on Wall Street”, the police begin to move in. To date, 23 arrests of peaceful protesters have been recorded in New York. On Broadway, demonstrators are dragged off the pavements and taken away by police.

One of them is a young white woman, who I see being hustled along by a number of officers. “I was standing on the sidewalk. Apparently that's illegal now,” she says, as police twist her hands and shove her into a car.

Unions join Wall Street protesters

Unions have lent their muscle to the long-running protests against Wall Street and economic inequality, with their members joining thousands of protesters in a lower Manhattan march as smaller demonstrations flourished across the US.

Protesters in suits and T-shirts with union slogans left work early to march with activists who have been camped out in Zuccotti Park for days. Some marchers brought along their children, hoisting them on to their shoulders as they walked down Broadway.

"We're here to stop corporate greed," said Mike Pellegrino, an NYC Transit bus mechanic from Rye Brook. "They should pay their fair share of taxes. We're just working and looking for decent lives for our families."

Of the camping protesters, he said: "We feel kinship with them. We're both looking for the same things."

People gathered in front of the courthouses that encircle Foley Square, then marched to Zuccotti Park, where they refuelled with snacks and hurriedly painted new signs as the strong scent of burning sage wafted through the plaza.

Previous marches have resulted in mass arrests. Police said there were about a dozen arrests last night, mostly for disorderly conduct. But at least one arrest was for assaulting a police officer; authorities said a demonstrator knocked an officer off his scooter.

The protesters have varied causes but have spoken largely about unemployment and economic inequality and reserved most of their criticism for Wall Street. "We are the 99%," they chanted, contrasting themselves with the wealthiest 1% of Americans.

Susan Henoch, 63, of Manhattan, said she was a "child of the '60s" and came out to the park for the first time on Wednesday. She held a sign that read "Enough".

"It's time for the people to speak up," she said. "Nobody's listening to us, nobody's representing us. Politics is dead.

"This is no longer a recognisable democracy. This is a disaster," she said.